U.S. patent application number 10/332821 was filed with the patent office on 2004-03-11 for control valve for liquids.
Invention is credited to Huebel, Michael, Stein, Juergen.
Application Number | 20040046138 10/332821 |
Document ID | / |
Family ID | 7684603 |
Filed Date | 2004-03-11 |
United States Patent
Application |
20040046138 |
Kind Code |
A1 |
Stein, Juergen ; et
al. |
March 11, 2004 |
Control valve for liquids
Abstract
The current invention relates to a valve (1) for controlling
fluids, which has a piezoelectric actuator for actuating a valve
element (3, 4), wherein the valve element (3, 4) moves out of a
valve body (16) when actuated. A stroke control is embodied between
the piezoelectric actuator and the valve element (3 ,4). The valve
also has a stop device (8) for limiting the stroke h.sub.1 of the
valve element (3, 4).
Inventors: |
Stein, Juergen; (Illingen,
DE) ; Huebel, Michael; (Gerlingen, DE) |
Correspondence
Address: |
RONALD E. GREIGG
GREIGG & GREIGG P.L.L.C.
1423 POWHATAN STREET, UNIT ONE
ALEXANDRIA
VA
22314
US
|
Family ID: |
7684603 |
Appl. No.: |
10/332821 |
Filed: |
June 13, 2003 |
PCT Filed: |
May 10, 2002 |
PCT NO: |
PCT/DE02/01703 |
Current U.S.
Class: |
251/129.06 ;
251/284 |
Current CPC
Class: |
F02M 61/161 20130101;
F02M 61/168 20130101; F02M 51/0603 20130101; F02M 61/08 20130101;
F02M 61/12 20130101; F02M 2200/304 20130101 |
Class at
Publication: |
251/129.06 ;
251/284 |
International
Class: |
F16K 031/02 |
Foreign Application Data
Date |
Code |
Application Number |
May 12, 2001 |
DE |
101 23 218.7 |
Claims
1. A valve for controlling fluids, which has a piezoelectric
actuator for actuating a valve element (3, 4), wherein the valve
element (3, 4) moves out of a valve body (16) when actuated,
characterized in that a stroke control is embodied between the
piezoelectric actuator and the valve element (3 ,4) and that the
valve also has a stop device (8) for limiting the stroke (h.sub.1)
of the valve element (3, 4).
2. The valve according to claim 1, characterized in that the stop
device (8) is embodied as a mechanical stop.
3. The valve according to claim 1 or 2, characterized in that the
valve element (3) has a shoulder (13) against which the stop device
(8) rests.
4. The valve according to one of claims 2 or 3, characterized in
that the mechanical stop (8) is embodied of one piece.
5. The valve according to claim 2 or 3, characterized in that the
mechanical stop is comprised of an adjusting ring (9) and a
clamping piece (10).
6. The valve according to one of claims 1 to 5, characterized in
that the mechanical stop (8) has a projecting region (23) with a
length (h.sub.2), and the maximal stroke (h.sub.1) of the valve
element (3) is determined by the projecting region (23).
7. The valve according to one of claims 1 to 6, characterized in
that the valve element is embodied as a valve needle (3).
8. The valve according to claim 7, characterized in that a pressure
pin (4) is disposed between the valve needle (3) and the
piezoelectric actuator.
9. The valve according to one of claims 1 to 8, characterized in
that the mechanical stop (8) is welded to the valve element (3,
4).
10. The valve according to claim 1, characterized in that the stop
device is embodied as a hydraulic stop.
Description
PRIOR ART
[0001] The current invention relates to a valve for metering or
controlling fluid flows or fluids and in particular a fuel
injection valve for a reservoir injection system.
[0002] Valves for controlling fluids are known in various
embodiments. For example, DE 43 32 124 A1 has disclosed a fuel
injection valve, which has an adjustable stroke limitation for a
valve needle. The stroke limitation includes an actuator and a
limitation stop, which is guided so that it can move in a guide
bore of the fuel injection valve. The actuator is disposed on the
stroke limitation in such a way that the position of the stroke
limitation is determined through activation of the actuator.
Consequently, a valve needle stroke can be changed in a range of
approx. 0.1 mm.
[0003] An adjustable stroke limitation is also known, which is
comprised of a ring, which is disposed around the valve needle and
has a slot extending through it. This through slot has an actuator
disposed in it, which lengthens when activated so that the stroke
limitation is clamped at a particular position in a guide bore.
This permits a limiting stop to be produced, which permits a stroke
adjustment over a very large range.
[0004] The stroke limitations that can be adjusted by means of
piezoelectric actuators can in fact be individually adjusted during
operation of the valve, but their design is relatively complex.
Valves are also known that open toward the outside, i.e. valves
whose valve element moves out of the valve housing when actuated,
but these valves do not have stroke stops. During operation,
however, temperature influences can cause different elongations of
the components, which can result in different injection quantities,
jet angles, and penetration, particularly in outwardly opening
valves.
ADVANTAGES OF THE INVENTION
[0005] The valve according to the invention for metering or
controlling fluid flows or fluids, with the characterizing features
of claim 1, has the advantage over the prior art that the stroke of
a valve element is limited to a maximum in an outwardly opening
valve. According to the invention, an outwardly opening valve is
provided, which has a piezoelectric actuator, for example, for
actuating the valve element. The piezoelectric actuator actuates
the valve element directly, i.e. in a direct, mechanical fashion,
so that the stroke of the valve element is controlled. According to
the invention, a stop is also provided in order to limit the stroke
of the valve element. As a result, according to the invention, the
tolerances in the valve can be reduced to thermally or mechanically
induced tolerances comprised of pressure influence and longitudinal
expansions. The sum of these tolerances is less than a stroke
tolerance of the piezoelectric actuator without a stop. The
invention consequently permits particularly precise injection
processes, particularly in a fuel injection, wherein the injection
quantities, the jet angles, and the penetration can be precisely
maintained. This has a positive influence on the combustion
process. Furthermore, the invention can even minimize a dynamic
influence. The possibility of also using an outwardly opening valve
to inject at an angle into a combustion chamber makes it possible
to also use the valve according to the invention for motors in
which, for space reasons, the injection valve cannot be installed
in the middle of the cylinder head. Furthermore, by placing the
stop in various positions, the penetration and jet shape of the
injection pattern can be adapted to different combustion chambers
and different motors.
[0006] In order to produce the simplest possible design, the stop
is preferably embodied as a mechanical stop. It is particularly
preferable for the mechanical stop to be comprised of an adjusting
ring and a clamping piece for fixing the position of the adjusting
ring.
[0007] In order to have a definite contact point on the valve
element, the valve element preferably has a shoulder against which
the adjusting ring rests.
[0008] According to another preferred embodiment of the current
invention, the adjusting ring and the clamping piece are embodied
of one piece in order to reduce the number of parts.
[0009] The adjusting ring preferably has a projection in order to
establish the maximal stroke of the valve element.
[0010] It is particularly preferable for the valve element to be
embodied as a valve needle. In order to prevent the valve needle
from tilting, it is preferably doubly guided in the valve body.
[0011] According to another preferred embodiment of the current
invention, the valve element is comprised of two parts: a valve
needle and a pressure pin. The pressure pin is directly connected
to the piezoelectric actuator for actuating the valve element.
[0012] In order to permit a secure connection between the
mechanical stop and the valve element, the clamping piece of the
stop is preferably welded to the valve element.
[0013] According to another different embodiment of the current
invention, the stop device is embodied as a hydraulic stop. This
permits a different maximal stroke of the valve element to be set
in a simple manner, for example by setting different fluid filling
levels of the hydraulic stop chamber. This permits a particularly
simple adaptation of the valve to different combustion chambers and
motors.
[0014] It is particularly preferable for the valve according to the
invention to be used as a fuel injection valve in a reservoir
injection system.
[0015] According to the invention, therefore, a valve is produced
in which a stroke limiting stop is provided, which can be adapted
with particular ease to different combustion chambers and different
motors. The stop is not embodied as adjustable; in lieu of this,
the stop is adapted to the different requirements during
installation. Consequently, the valve according to the invention
can be embodied in a particularly compact manner and can be
disposed in a wide variety of positions in an engine
compartment.
DRAWINGS
[0016] Several exemplary embodiments of the invention are shown in
the drawings and will be explained in detail in the subsequent
description.
[0017] FIG. 1 shows a schematic section through a fuel injection
valve according to a first exemplary embodiment of the current
invention,
[0018] FIG. 2 shows an enlargement of the valve shown in FIG. 1, in
the region containing the stop,
[0019] FIG. 3 shows a schematic partial section through a valve
according to a second exemplary embodiment of the current
invention,
[0020] FIG. 4 shows a schematic partial section through a valve
according to a third exemplary embodiment of the current invention,
and
[0021] FIG. 5 shows a schematic partial section through a valve
according to a fourth exemplary embodiment of the current
invention.
DESCRIPTION OF THE EXEMPLARY EMBODIMENTS
[0022] FIGS. 1 and 2 show a fuel injection valve 1 according to a
first exemplary embodiment of the current invention.
[0023] As shown in FIG. 1, the valve 1 has a piezoelectric
actuator, not shown, and a valve needle 3. The valve needle 3 is
directly connected to a foot 2 of the piezoelectric actuator by
means of a pressure pin 4, thus producing a so-called stroke
control of the valve 1 in which the piezoelectric actuator
mechanically actuates the valve element 3 directly. As shown in
FIG. 1, the foot of the piezoelectric actuator is placed against
the pressure pin 4 by means of a spring element 12, thus producing
a positive engagement.
[0024] The valve needle 3 is disposed in a valve body 16, which is
connected to a valve holder 17. As shown in FIG. 1, the valve 1 is
an outwardly opening valve in which the valve needle 3 is moved out
of the valve body 16 when actuated. When it is not actuated, the
valve needle 3 closes a valve seat 5. A first valve guide 6 and a
second valve guide 7 are provided in order to prevent the valve
needle 3 from tilting. The first valve guide 6 is comprised of
several rib-like protrusions, which slide against the valve body 16
and have openings between them.
[0025] In addition, a spring clamping piece 15 is fastened to the
pressure pin 4 and serves as a spring seat for a return spring 14.
At its other end, return spring 14 is supported against the valve
body 16. Fuel is supplied through an inlet conduit 18 to an annular
gap 19 disposed around the valve needle 3.
[0026] According to the invention, a stop 8 is also provided, which
as shown in FIG. 2 in particular, includes an adjusting ring 9 and
a clamping piece 10. The clamping piece 10 is affixed to the
pressure pin 4 by means of a welding seam 11. The adjusting ring 9
rests against a shoulder 13 of the valve needle 3 and has an
annular projection 21, which in the transition the region between
the valve needle 3 and the pressure pin 4, protrudes into a recess
22 embodied in the pressure pin. In addition, the adjusting ring 9
has a projection 23 with a length h.sub.2. Consequently, the
adjusting ring 9 embraces the end of the valve needle 3 oriented
away from the valve seat 15.
[0027] FIG. 2 also shows the maximal stroke height h.sub.1. The
maximal stroke height h.sub.1 of the valve is determined by the
distance between the adjusting ring 9 and the end of the stop
surface 16a on the valve body 16.
[0028] The assembly of the valve 1 according to the invention
occurs in such a way that first, the valve needle 3 is inserted
into the valve body 16 from the front. Then, the distance between
the actuator end 16a of the valve body 16 and shoulder 13 of the
valve needle 3 is measured. Depending on this distance between the
shoulder 13 and the valve body 16, a suitable adjusting ring 9 with
a suitable projection h.sub.2 is selected to produce a desired
maximal stroke h.sub.1. The adjusting ring 9 is slid onto the valve
needle 3 from the rear until it rests against the shoulder 13 on
the valve needle 3. Then, the clamping piece 10 is slid on from the
rear and is connected to the pressure pin 4 by means of
welding.
[0029] Then the return spring 14 and the spring clamping piece 15
are slid onto the needle and the return spring 14 is prestressed to
a desired prestressing force by means of the spring clamping piece
15. The spring clamping piece 15 is attached to the pressure pin 4
by means of welding, for example. Then the valve holder 17 is slid
onto the valve body 16 and the two are connected to each other by
means of welding, for example. The weld between the valve body 16
and the valve holder 17 is disposed at a point, which is as far as
possible from the needle guide 7. This prevents a negative effect
due to a possible welding-induced distortion.
[0030] The operation of the valve according to invention will be
described below. When an injection is to be executed, the
piezoelectric actuator is activated, causing it to expand counter
to the spring force of the spring 12, in the direction of a center
line x-x of the valve. This stroke of the piezoelectric actuator is
transmitted to the valve needle 3 by means of the actuator foot and
the pressure pin 4. The pressure pin 4 and the valve needle 3 are
attached to each other. As a result, the valve needle 3 lifts away
from its valve seat 5 so that an injection of fuel occurs. The
maximal stroke h.sub.1 of the valve needle 3 is established by the
mechanical stop 8, which is affixed to the pressure pin 4. Then if
length changes of the individual components occur, for example due
to temperature changes, the stop 8 prevents this from causing
changes in the opening at the valve seat 5 that is unblocked by the
valve needle 3. This keeps the injection quantity constant during
operation and prevents the jet angle and the penetration from being
influenced, which is necessary particularly in jet-controlled
combustion processes.
[0031] When the injection is to be terminated, the piezoelectric
actuator is triggered again so that it shortens. Then by means of
the spring clamping piece 15 and the pressure pin 4, the return
spring 14 presses the valve needle 3 back into its starting
position and closes the valve seat 5. This terminates the
injection.
[0032] FIG. 3 shows a valve according to a second exemplary
embodiment of the current invention. Parts that are the same or
function in the same manner are provided with the same reference
numerals as in the first exemplary embodiment.
[0033] In contrast to the first exemplary embodiment, in the second
exemplary embodiment shown in FIG. 3, the stop 8 is embodied of one
piece. In other words, in lieu of the adjusting ring 9 and the
clamping piece 10 in the first exemplary embodiment, only an
annular stop 8 is provided. The length of the stop 8, in particular
the length h.sub.2 of the projection beyond the shoulder 13 of the
valve needle 3, determines the maximal stroke height h.sub.1. In
order to permit the achievement of different maximal stroke heights
h.sub.1, it is necessary to produce a number of annular stops 8
with different-sized projections h.sub.2. Otherwise, the second
exemplary embodiment corresponds to the first exemplary embodiment
so that reference can be made to description given there.
[0034] FIG. 4 shows a valve 1 according to a third exemplary
embodiment of the current invention. Parts that are the same or
function in the same manner are provided with the same reference
numerals as in the first and second exemplary embodiment.
[0035] In contrast to the preceding exemplary embodiments, in FIG.
4, no shoulder is provided on the valve needle 3. The maximal
stroke h.sub.1 of the valve is determined, for example, by means of
a feeler gage and then the stop 8 is attached to the valve needle 3
by means of welding, for example. The feeler gage is withdrawn
again after the welding. As shown in FIG. 4, the stop 8 is once
again embodied of one piece as in the second exemplary embodiment.
Consequently, various maximal strokes h.sub.1 can be set in
different valves by keeping different feeler gages on hand.
[0036] FIG. 5 shows a fourth exemplary embodiment according to the
current invention. Parts that are the same or function in the same
manner are provided with the same reference numerals as in the
preceding exemplary embodiments.
[0037] The fourth exemplary embodiment essentially corresponds to
the third exemplary embodiment in which no shoulder is provided on
the valve needle 3. FIG. 5, however, shows the connection between
the valve body 16 and valve holder 17 in more detail. As shown in
FIG. 5, the valve body 16 and the valve holder 17 are attached to
each other by means of a welding seam 20. It should be noted that a
connection between the valve body 16 and the valve 17 could also be
produced by means of a thread.
[0038] Consequently, the current invention relates to a valve 1 for
controlling fluids, which has a piezoelectric actuator for
actuating a valve element 3, 4, wherein the valve element 3, 4
moves out of a valve body 16 when actuated. A stroke control is
embodied between the piezoelectric actuator and the valve element
3, 4. The valve also includes a stop device 8 in order to limit the
stroke h.sub.1 of the valve element 3, 4.
[0039] The foregoing description of exemplary embodiment according
to the current invention is solely intended for illustrative
purposes and is not intended to limit the invention. Various
changes and modifications are possible without going beyond the
scope of the invention and its equivalents.
* * * * *